Washington (CNN) – President Barack Obama’s second nominee to head the Transportation Security Administration side-stepped questions Wednesday about whether he supports unionizing the nation’s 40,000 airport screeners, but acknowledged the president’s support for unionization of screeners and said any such plan should be done in a way that would not hurt national security. Treading lightly on a topic that helped to derail the president’s first nominee, Robert Harding likened his role to those of presidential appointees who are advising the president on closing Guantanamo Bay or allowing gays in the military. “My recommendations would be very unbiased, they would be very factual and I think that’s what I owe the secretary (of Homeland Security) and the president,” Harding said.